Go to latest version breaks for /src/ when item was renamed

[jyn514]

I noticed this while investigating #357: any time you click 'Go To Latest' while viewing source code, it redirects to https://docs.rs/:crate/:version/src/:crate/?search=rs. This is clearly not desired behavior (it gives a 404).

Don't have time to debug right now but the relevant code is

docs.rs/src/web/rustdoc.rs

Line 293 in d9d7a33

fn path_for_version(req_path: &[&str], target_name: &str, conn: &Connection) -> String {

.

[jyn514]

I can't reproduce this bug 😆

[jyn514]

Ok it turns out the bug is much more limited than I thought which is good - it's only if the item was renamed or deleted. Test case: https://docs.rs/pyo3/0.2.7/src/pyo3/objects/exc.rs.html. This redirects to https://docs.rs/pyo3/0.8.4/src/pyo3/?search=rs, which gives a 404. I think the right thing to do would be to redirect to https://docs.rs/pyo3/0.8.4/pyo3/?search=exc - that doesn't keep you in source view, but you still get a search page.

[jyn514]

Mentoring instructions:

This only requires changing the frontend.

1. Check here if the 3rd part of the URL is src; if so, don't add it to crate_root.
2. Currently, we unconditionally search for the 2nd part of the filename, which for source files is the file extension (usually .rs). Change this to search for the 1st part of the filename if the 3rd part of the URL is src.

There's more information about this in the comments for the function I linked.

Note that the URL may include both a platform and src, e.g. https://docs.rs/pyo3/0.2.7/x86_64-pc-windows-msvc/src/pyo3/lib.rs.html.

[Zexbe]

I found another example, If you go to this link
https://docs.rs/playground/0.1.0/playground/
The go to latest version has a bad link that goes to
https://docs.rs/playground/0.1.1/playground/?search=playground

[jyn514]

This is #502, I have an open PR waiting for me to add unit tests review: #509

[jyn514]

This has been half-fixed - we now redirect to https://docs.rs/pyo3/0.13.2/pyo3/?search=rs, which is correct except that the search query is wrong.